Розширення технологічних можливостей гвинтових механізмів машин

Abstract

Schlieren imaging is a method to visualize differences in refractive index within a medium. It is an inexpensive, yet powerful and straightforward tool, for sensitive and high-resolution visualization of gas flows. Here, heated cold gas microthrusters were studied with schlieren imaging techniques. The thruster chips are manufactured using MEMS technology, and measure 22*22*0.85 mm. The nozzles are approximately 20 µm wide at the throat, and 350 µm wide at the exit. Through these studies, verification and direct visualization of the functionality of the thrusters were possible. At atmospheric pressure, slipping of the exhaust was observed, due to the severe overexpansion of the nozzle. In vacuum, the nozzle was underexpanded, and the flow was seen to be supersonic. There was a measurable change in the exhaust with heaters activated. It was also shown that the method can be used to detect leaks, making it a valuable, quick, safe, and inexpensive aid in quality control of the thrusters